Re: [Libguestfs] [PATCH] v2v: Add --print-estimate option to print source size estimate.

On Tue, Aug 14, 2018 at 09:31:06PM +0300, Nir Soffer wrote: > On Tue, Aug 14, 2018 at 8:29 PM Richard W.M. Jones <rjones(a)redhat.com&gt; > wrote: > > > This option prints the estimated size of the data that will be copied > > from the source disk. > > > > For interest, the test prints: > > > > 3747840 ../test-data/phony-guests/windows.img > > Estimate: 3710976 > > > > Why not use qemu-img measure on the overlay? Yes this would be better, but oddly it doesn't work properly when the output format is set to 'raw': /usr/bin/qemu-img 'measure' '-f' 'qcow2' '-O' 'raw' '--output=human' '/home/rjones/d/libguestfs/tmp/v2vovl62b7c2.qcow2' required size: 6442450944 fully allocated size: 6442450944 However it's OK if the output format is set to 'qcow2': /usr/bin/qemu-img 'measure' '-f' 'qcow2' '-O' 'qcow2' '--output=human' '/home/rjones/d/libguestfs/tmp/v2vovla53d7c.qcow2' required size: 1047986176 fully allocated size: 6443696128 I guess it ignores sparseness of raw images, but I can't see a way to specify that on the command line. OTOH the qcow2 figure is probably a good enough guess for our purposes (ie. estimating how much data will be copied).